Lithium-based cells or batteries often comprise cathodes of transition metal oxides which are used as intercalation compounds. The intercalation reaction involves the interstitial introduction of a guest species, namely, lithium into the host lattice of the transition metal oxide, essentially without structural modification of the host lattice. Such intercalation reaction is essentially reversible because suitable transition states are achieved for both the forward and reverse of the intercalation reaction.
The basic components of a lithium cell typically include a lithium anode, a separator, and a metal oxide intercalation cathode active material such as a vanadium oxide compound also referred to as vanadates or vanadate compounds. The cathode is usually a mixture of such oxide compound and other components such as graphite and an electrolyte/binder which provide ionic transport. During cell operation, incorporation of lithium in the metal oxide occurs. Some vanadates have high initial capacities, which, however, rapidly decline especially in the first cycles. Many metal oxides are prepared in a complex process by mixing precursor components containing an alkali metal with vanadium pentoxide and then baking the mixture to a temperature in the range of about 700.degree. C. (centigrade) to 800.degree. C. to cause formation of the product. The molten product is then cooled and ground up into a powder. The melt process has certain disadvantages because it is difficult to handle molten metal oxides at high temperatures and special procedures are required; there is a reaction between the molten product and containers used for conducting the reaction which thereby causes contamination of the product; and a significant amount of mechanical energy is required to grind the cooled, solidified products into a powder for inclusion in a cathode composition of an electrochemical cell. Despite these difficulties, typical melt processes, as described in U.S. Pat. No. 5,013,620, continue to be used to obtain positive electrode active material, such as LiV.sub.3 O.sub.8. Recently, it has been suggested to form vanadium oxide compounds by reaction of a precursor oxide with an alkali hydroxide such as LiOH (Pistoia U.S. Pat. No. 5,039,582). Still another approach relies on reaction of an alkali with metavanadate (VO.sub.3) in an acidified solution. This approach has been used with the alkali being potassium or sodium. (Solid State Ionics 40/41 (1990) 585-588; J. Power Sources 43/44 (1993) 561-568.) Despite the many available compounds and methods, it is desirable to have a new active material which has a high specific energy, high cycle life and high rate capability; and a method for preparing such active material which is relatively simple and economical, which does not require handling metal oxide constituents in a molten state, and which achieves good conversion of the starting materials to the final metal oxide product.